Multiphase Chopper Power Supply Phase Failure Management
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Solution Overview
Problem
Existing multiphase chopper power supply devices fail to continue operation if one or more phases experience an open-circuit failure, leading to potential overheating and fire, and can result in the power supply device being unable to charge vehicle batteries, causing vehicle shutdown.
Innovation Solution
A power supply device with a multiphase chopper configuration that includes a power generation unit, switching elements driven in switched mode, a current detector, a smoothing capacitor, and a failure determination means to detect and manage current imbalances across phases, ensuring the non-failed phases do not exceed their current capacity, allowing operation to continue even if one or more phases fail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multiphase chopper configuration is used to reduce current per phase and output ripples, then productivity and efficiency are improved, but reliability deteriorates because the system cannot continue operation if one phase fails
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the current detected by the current detector and adjusts the duty ratio of switching elements in real-time. When a phase failure is detected through current imbalance feedback, the control unit automatically reduces the duty ratio of remaining phases to prevent overcurrent, enabling the system to continue operating safely without manual intervention.
Solution Approach 2:
The patent makes the system dynamic by allowing the duty ratio of switching elements to vary automatically based on operating conditions and failure states. The control unit dynamically adjusts the duty ratio from normal operation levels to reduced levels when phase failures occur, transforming the system from a static fixed-duty-ratio design to an adaptive dynamic design that responds to changing conditions.
2Power
If the duty ratio of remaining phases is increased to compensate for failed phases, then power output is maintained, but the withstanding current of switching elements is exceeded causing overheating and potential fire
Solution Approach 1:
The patent applies preliminary anti-action by proactively reducing the duty ratio of remaining phases when a phase failure is detected, before overcurrent conditions can cause overheating or fire. The control unit preemptively adjusts the duty ratio downward to prevent harmful effects, rather than allowing current to increase to compensate for the failed phase.
Solution Approach 2:
The patent converts the harmful effect of phase failure into a beneficial operational mode by detecting the failure and reconfiguring the remaining phases to operate at reduced duty ratios. This transforms a potentially dangerous situation (overcurrent, overheating) into a safe degraded operation mode that prevents damage while maintaining limited power supply capability.
3Device complexity
If simple current detection is used, then device complexity is reduced, but measurement precision deteriorates because current imbalances cannot be accurately detected at all switching transitions
Solution Approach 1:
The patent applies preliminary action by detecting current values at specific predetermined timing points (falling edges or rising edges of control signals) before switching transitions occur. This timing strategy allows accurate detection of current imbalances at critical moments without requiring continuous high-frequency monitoring, reducing detection system complexity while maintaining sufficient measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous operation by detecting and managing current imbalances, preventing overheating and ensuring the power supply device can maintain functionality even if one or more phases fail, thereby preventing vehicle shutdown due to battery charging issues.
Implementation Method 1
each of the chopper sections of the phases includes a switching element driven in switched mode... so as to convert the DC voltage from the power generation unit into a predetermined output voltage
Implementation Method 2
a reactor for smoothing a voltage converted by the switching element and the rectifying element
Implementation Method 3
a smoothing capacitor for smoothing an output voltage from the multiphase chopper
Implementation Method 4
a current detector for detecting an output current from the multiphase chopper
Data Source
AI summary
A power supply device includes a failure determination means that detects, based on a current detected by a current detector, a failure of the switching elements of each of the chopper sections, and the failure determination means obtains values of the current detected by the current detector at the timing of falling edges of control signals to the switching elements of each of the chopper sections, determines the failure when the obtained current values differ from each other, and transmits a failure signal to a generation control means. When receiving the failure signal, the generation control means limits an output current from a generator in a way such that the withstanding current of a non-failed chopper section out of the chopper sections of the phases is not exceeded.